(19)

(11)

EP 2 732 313 A2

(12)

(88) Date of publication A3: 18.07.2013 (43) Date of publication: 21.05.2014 Bulletin 2014/21 (21) Application number: 12740642.9 (22) Date of filing: 12.07.2012

(51) International Patent Classification (IPC):  G01V 1/22(2006.01) (86) International application number: PCT/GB2012/051652 (87) International publication number: WO 2013/011283 (24.01.2013 Gazette 2013/04)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (30) Priority: 15.07.2011 GB 201112154 (71) Applicant: OptaSense Holdings Limited Hampshire GU14 0LX (GB)	(72) Inventors: LEWIS, Andrew Bristol BS20 7FS (GB) RUSSELL, Stuart Bristol BS20 7FS (GB) (74) Representative: Davies, Philip  Haseltine Lake LLP Redcliff Quay 120 Redcliff Street Bristol BS1 6HU Bristol BS1 6HU (GB)